面向双臂协同的阻抗控制方法研究

发布时间：2018-06-24 01:03

本文选题：双臂协同 + 运动学约束　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：现代生产对智能化、协同性及功能性的要求不断提高,传统的单个机器人在固定工位的程序化操作已经很难满足当前工厂智能化的要求,而双臂机器人由于其功能性强、灵活性高、负载能力强等特点得到了广泛的关注。但是,双臂机器人在协同操作时存在较强的运动学约束及复杂的动力学耦合问题,因此双臂机器人之间的协调运动及力控制成为其在工业环境下进行推广和使用需要解决的关键问题。针对于传统的双臂协同运动过程中约束较多、易碰撞,及力控制过程对精确动力学模型的要求较高、力追踪误差较大等问题,本文重点开展了对双臂协同作业的运动协调及力控制问题的研究,建立了双臂运动学约束方程,进行了双臂避碰规划,利用间接自适应阻抗控制方法实现了双臂解耦的操作力控制,并通过仿真及实验验证了所提方法的有效性,具体的研究内容如下:针对于双臂机器人的协同运动问题,通过运动学约束方程及避碰方法实现了对双臂的运动规划。本文首先建立了机器人的D-H坐标系,进行了正、逆解的求解,然后分析了双臂及被操作物体形成的封闭链,确定了双臂末端的位置及速度约束关系;对于双臂可能发生的碰撞,利用圆柱加半球的碰撞模型简化方法对双臂进行简化建模,在简化模型间最短距离计算的基础上,结合速度排斥场方法进行避碰规划,并通过仿真验证了约束方程及避碰方法的正确性。针对双臂力控制问题,本文利用间接自适应阻抗控制方法实现了对物体的紧协调操作。首先根据阻抗控制参数分析结果,结合基于遗传算法的寻优方法,获得了阻抗控制系统最优参数;利用被操作物体的动力学方程与运动状态信息,实现了双臂期望操作力的分配;基于双臂机器人末端力、位移信息,结合非线性最小二乘法拟合方法与碰撞函数,获得了未知环境参数以及双臂末端位移补偿量。在上述基础上,结合间接自适应阻抗控制方法,建立了有、无外界干扰的双臂协同控制策略。最后,本文搭建了双臂仿真及实验平台,在仿真上验证了双臂协调控制策略的有效性,并进行了双臂避碰及协同操作的实物实验,实现了双臂的无碰撞运动以及双臂对物体的夹持操作。此外,本文根据期望力的不同做了多组对比实验,得到了本文方法及传统方法在不同期望力下对目标力的追踪结果,验证了本文提出方法的正确性。
[Abstract]:The requirements of modern production for intelligence, cooperation and functionality are constantly improved. The programmed operation of traditional single robot in fixed position has been difficult to meet the requirements of intelligent factory, but the dual-arm robot has strong functionality. High flexibility, strong load capacity and other characteristics have been widely concerned. However, there are strong kinematics constraints and complex dynamic coupling problems in the cooperative operation of the dual-arm robot. Therefore, the coordination of motion and force control between dual-arm robots has become a key problem to be solved in the industrial environment. In the traditional two-arm cooperative motion process, the constraints are more, the collision is easy, and the force control process requires higher precise dynamic model, and the force tracking error is large, and so on. This paper focuses on the study of motion coordination and force control of dual-arm cooperative operation, establishes the two-arm kinematics constraint equation, and carries out the dual-arm collision avoidance planning. The indirect adaptive impedance control method is used to realize the two-arm decoupling force control, and the effectiveness of the proposed method is verified by simulation and experiments. The specific research contents are as follows: aiming at the cooperative motion of the dual-arm robot, The kinematics constraint equation and collision avoidance method are used to realize the motion planning of both arms. In this paper, the D-H coordinate system of the robot is established, and the forward and inverse solutions are solved. Then, the closed chain between the two arms and the operated object is analyzed, and the position and velocity constraints at the end of the two arms are determined. The simplified method of collision model with cylinder and hemispheres is used to simplify the two-arm model. On the basis of simplifying the calculation of the shortest distance between the models, the collision avoidance planning is carried out by combining the velocity exclusion field method. The correctness of constraint equation and collision avoidance method is verified by simulation. In order to solve the problem of double arm force control, the indirect adaptive impedance control method is used to realize the compact and coordinated operation of the object. According to the results of impedance control parameter analysis and the optimization method based on genetic algorithm, the optimal parameters of impedance control system are obtained. Based on the end force and displacement information of the two-arm robot and the nonlinear least square fitting method and the collision function, the unknown environment parameters and the displacement compensation at the end of the two arms are obtained. On the basis of the above, combined with the indirect adaptive impedance control method, a two-arm cooperative control strategy with and without external interference is established. Finally, the simulation and experiment platform of double arms is built, and the effectiveness of the coordinated control strategy of both arms is verified by simulation, and the physical experiments of double arms collision avoidance and cooperative operation are carried out. The collision-free motion of the two arms and the clamping operation of the two arms to the object are realized. In addition, according to the different expected forces, this paper makes a number of comparative experiments, and obtains the tracking results of the target forces under different expected forces by the method and the traditional method, which verifies the correctness of the proposed method.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP242

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